Many lamps comprise a source of light within a housing that is configured to concentrate the light in a desired direction. For example, in the case of a searchlight or light house, the concentration is such that the light may be said to be collimated, in that rays emerge from the light in parallel. In many cases, it is also desirable that the direction of collimation can be scanned. This may be done with conventional lamps, for example, by rotating the whole lamp, or rotating the lens and mirror around the source of light. However, such scanning mechanisms may not be suitable for use in some devices, such as display devices, due to geometric and other factors.